I've done that at some places where there are SVT's on both sides of the drum riser.
my fender tuner has 2 outputs, 1 mutes when I tune, the other stays live.
I just run a cable from each output of the tuner to the input of the amps and it works just fine. FOH is getting signal from the tonehammer anyway, so it is just for stage volume.
"I really don't care how well some guitar guy plays Eruption in front of 15 cougars at a dive bar."